Random noise gave vital boost to primitive life

WHEN life began in the hostile conditions of early Earth, so many random mutations and errors would have plagued the first molecules struggling to copy themselves that explaining how longer or more complex forms ever evolved has been tough. But it seems that the right combination of random events or "biological noise" counteracted the high mutation rate, speeding up evolution.

A certain level of mutation is vital to provide the variation on which natural selection acts. But high levels of mutation limit the maximum length a molecule such as RNA can reach, because too many mutations will be introduced in each generation for the molecule to keep functioning. To get longer molecules, you need a protein that assists copying and lowers the mutation rate.

But how could such a protein have evolved? "It's a chicken and egg situation," says David Krakauer of the Santa Fe Institute in New Mexico. "To ...

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